Circular slide rule



FIG. 1 is a top, front, right perspective view of a circular slide rule, showing my new design;

FIG. 2 is a front elevation thereof;

FIG. 3 is a right side elevation thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a bottom view thereof; and

FIG. 6 is a rear elevation thereof.

The left side elevation is a mirror image of the right side.

The circular dial shown in the center of the circular slide rule in FIGS. 1 and 2 is rotatable, and will appear in various rotational positions. 

The ornamental design for a circular slide rule, as shown and described. 